In manufacturing an electronic device, a processing of etching a layer to be etched on a workpiece to be processed (“workpiece”) is performed so as to form a pattern on the etched layer of the workpiece. Attempts to etch a transition metal-containing film as an etched layer are performed recently. Such a film may be used as a film that constitutes a part of, for example, a magnetic tunnel junction (MTJ).
As for etching a film including a transition metal, an Ar ion milling method is usually used. However, the Ar ion milling method is difficult to perform fine machining and may also cause a problem in that etching products may be re-attached to a workpiece. For this reason, a transition metal-containing film is also etched by a plasma etching using a halogen gas. Such a technology is disclosed in, for example, Japanese Patent Laid-Open Publication No. 2003-282844.